Has anyone noticed that Chris was actually never involved in the prank? He was passed out with Josh in the beginning. Which makes me wonder why Josh would go after Chris when he was never involved in the prank.
Actually, this topic has been discussed pretty extensively in the fandom! I’m glad you asked, though, because this was one of my first questions as well once I really started getting into Until Dawn.
I would try to find some sources of posts that explain this better, but I’m unfortunately pretty unorganized with the theories I find. They’re lost deep in the void of my 4000+ likes, so I’ll just try to summarize.
Of course, I’m rubbish at summarizing, so sit back, buckle up, and get ready for an info dump.
The most obvious answer is that Josh is really just punishing Ashley for her involvement, and only involving Chris because he sees it as an opportunity to push them together. This is foreshadowed by the potential line of dialogue: “They just need something to bond over, y'know? Some sort of traumatic event to send them into each other’s arms.” But this theory seems to be oversimplifying it a bit; it fails to explain why he doesn’t involve Jess, Mike, Emily, and Matt (who all also took place in the prank) and DOES target Sam, who tried to stop it.
My personal favorite interpretation of this is a combination of two other theories I saw here on Tumblr: that he specifically targeted his closest friends - including Chris - as a way of punishing himself, and that he thought he was helping them by making them the heroes of his viral video.
At the beginning of the game, Chris, Ashley, and Sam are Josh’s highest three relationships (strangely enough, Sam is actually tied with Jess, but I won’t get into that for now). These are Josh’s best friends, the ones who are most friendly and concerned for him in early chapters. According to this theory, it makes sense that Josh, who canonically has severe delusions (thinking the others will laugh off the prank, etc), would think that he’s doing his friends a favor by making them stars of the prank he thought would be so popular, there wouldn’t be “enough hard drives in China” for all the views it’ll get.
The first theory mentioned is a little harder to prove or explain, but the basic idea is that Josh feels responsible for his sisters’ disappearance (his hallucination of Beth says “Why didn’t you save us, Josh? Why did you want us to die?”), so in his mind he’s punishing the person truly at fault - himself - by terrorizing and thus alienating those closest to him.
If anyone can find the original links to these theories (which do a much better job of explaining them than me), please feel free to reblog with them attached! I’d like to get the credit back to those who deserve it.